Reversible self-propelled center pivot sprinkler system

Abstract

A reversible self-propelled center pivot sprinkler system comprising a central pivot having an overhead water supply pipe extending outwardly therefrom supported by a plurality of drive towers. A drive and control apparatus is provided on each of the towers to propel the towers and water supply pipe around the central pivot point in an aligned condition. The drive apparatus is connected to a trojan bar which is reciprocatably mounted on the tower and which is provided with an automatically controlled movable double dog on at least one end thereof for engagement with drive lugs on at least one of the drive wheels of the tower. The double dog is normally in position so that movement of the trojan bar in one direction will cause the dog to engage the wheel drive lugs so that the tower will be moved in a forwardly direction. The double dog is automatically moved to a second position so that the dog will engage the wheel drive lugs as the trojan bar is moving in a second direction to cause the tower to be moved rearwardly. The double dog comprises a hydraulic cylinder operatively connected to a reversible trojan bar dog having opposing dog surfaces. A double ratchet-type brake is provided on the tower to prevent the tower from undesirable rolling in a direction opposite to the direction of driving travel. The double ratchet-type brake may be operatively interconnected to the double dog whereby remote control or operation of the double dog also causes the double ratchet-type brake to be moved to permit the tower to roll in the desired direction while preventing undesirable rolling in the opposite direction.

I claim: 
     
       1. A reversible self-propelled center pivot sprinkler system comprising, a water supply pipe movable about a center pivot point,   a plurality of spaced-apart, wheeled drive towers supporting said supply pipe above the area to be sprinkled,   a drive means on each of said towers to propel said towers to move said towers and supply pipe about said center pivot point,   each of said towers comprising a frame means having a pair of spaced-apart drive wheels rotatably mounted thereon,   a trojan bar means reciprocatably mounted on said frame means and movable between first and second positions, at least one double dog means on said trojan bar means for engagement with at least one of said drive wheels for selectively driving said wheel forwardly at times and for selectively driving said wheel rearwardly at other times,   a power means mounted on said frame means and being operatively connected to said trojan bar means to reciprocate said trojan bar means,   and a control means for controlling the operation of said power means so that the associated tower is propelled at the desired rate relative to the other towers in the system,   said double dog means comprising a plate means operatively pivotally mounted on said trojan bar means, said plate means having oppositely disposed dog surfaces formed therein, said plate means being selectively pivotally secured to said trojan bar means and being movable from a first position, wherein one of said dog surfaces will engage the lugs on said one wheel to drive said wheel and tower forwardly to a second position, wherein the other of said dog surfaces will engage the lugs on said one wheel to drive said wheel and tower rearwardly,   and a power cylinder pivotally connected to said plate means for moving said plate means between its first and second positions.   
     
     
       2. The system of claim 1 wherein rearward and forward stops are provided on said center pivot, said control means including means operatively connected to said power cylinder and being responsive to said rearward and forward stops.